JPH04265485A - Scroll compressor - Google Patents

Abstract

PURPOSE:To reduce fluid agitation by a balance weight and shaft vibration, and noise, and prevent the performance and reliability of a compressor from degrading with high-speed rotation by improving the shape and structure of the balance weight. CONSTITUTION:When a main spindle which is provided with an eccentric shaft part inserted in a boss protruding from the back surface of a revolving scroll at its shaft part rotates, the revolving scroll revolves against a stationary scroll. A balance weight 8 fixed at the main shaft is cylindrical, at a part of which a recessed part 8b where the boss of the revolving scroll is inserted is provided. The center line O2 of the recessed part 8b is eccentric from the center line Of of the main shaft by a distance 'g' almost equal to the revolving radius of the revolving scroll. The center of gravity of the balance weight 8 is eccentric in an opposite direction to the recessed part 8b from the center line Of of the main shaft, and the center line O1 of the cylindrical part coincides with Of or is eccentric by a distance L. A part of the balance weight 8 may be made of a material with higher specific gravity.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a scroll compressor having an improved balance weight shape and structure.

0002

[Prior art] A hermetic scroll compressor was developed in Japanese Patent Application Laid-Open No.
As disclosed in No. 271984, the refrigerant gas compressed by the scroll compression mechanism reaches the motor room from the upper discharge chamber through the communication path. The refrigerant gas then flows around the motor and out of the compressor discharge pipe. The balance weight, which rotates integrally with the main shaft of the compressor and protrudes toward one side of the main shaft, has a wedge-shaped end face in the rotating direction.

0003

[Problems to be Solved by the Invention] In the scroll compressor of the prior art described above, as shown in the shaded area in FIG. 6, the oil agitation area by the balance weight has a wide angular range, so the rotation speed is 10,000 rpm, etc. If we try to achieve higher speeds of the compressor, the amount of oil in the bearings will increase as the speed increases, and the oil agitation loss due to the balance weight will become extremely large. This loss increases in proportion to the cube or fourth power of the rotational speed and in proportion to the fourth power of the outer diameter of the balance weight, and the performance of the compressor decreases significantly. Furthermore, the bearing load acting on each bearing increases, and the mechanical loss in that area also increases. Additionally, the temperature rise on the bearing surface may become abnormally high, and seizure may occur. An object of the present invention is to solve the problem of performance deterioration and reliability deterioration caused by the speed increase of the compressor.

0004

[Means for Solving the Problems] The present invention discloses a shape in which the outer diameter of the balance weight is made smaller (thinner) and the area in which oil is stirred during one rotation can be made smaller. . The scroll compressor of the present invention has the structural features described in each claim.

[0005]

[Function] The function of the balance weight in the present invention is compared with that in the conventional machine, and is shown in FIGS. 5 and 6. As can be seen from this comparison, the area where oil is stirred during one rotation by the balance weight, that is, the area where oil moves (oil stirring area), is In terms of weight, it is several times smaller than that of conventional machines. When the central axis of the cylindrical balance weight is made to coincide with the central axis of the main shaft, the oil stirring area becomes substantially zero. Therefore, according to the configuration of the present invention, oil stirring loss due to the balance weight can be significantly reduced compared to conventional machines. Coupled with the reduction in bearing load due to the reduction in mechanical loss, the increase in oil temperature in the slewing bearing and main bearing is suppressed. These actions and effects become more pronounced as the speed increases. In addition, during high-speed operation, the movement and scattering of oil due to the balance weight is kept to a minimum, and as a result, the balance weight does not receive the extra fluid force (fluid reaction force) that occurs when swinging around, which reduces shaft vibration. It is possible to reduce the amount of noise and, in turn, reduce abnormal noise and noise.

[0006]

[Examples] Below, in the figures showing each example of the present invention,
Identical or corresponding parts are represented by the same reference numerals.

FIG. 3 is a vertical sectional view showing the overall structure of a hermetic scroll compressor according to an embodiment of the present invention.
is a cross-sectional view of the main part. A compressor section 100 is housed above and an electric motor section 3 is housed below in a closed container 1 consisting of upper and lower lid plates 2a, 2c and a body section 2b. The inside of the closed container 1 is divided into an upper chamber 1a (discharge chamber) and motor chambers 1b and 1c.

The compressor section 100 has a fixed scroll member 5 and an orbiting scroll member 6 that are engaged with each other to form a compression chamber (closed space) 7. The fixed scroll member 5 consists of a disc-shaped end plate 5a and a wrap 5b standing upright on the end plate and formed into an involute curve or a curve similar to this. It is equipped with The orbiting scroll member 6 consists of a disc-shaped end plate 6a, a wrap 6b standing upright thereon and formed in the same shape as the wrap of the fixed scroll, and a boss 6c formed on the surface opposite to the wrap of the end plate 6a. The frame 11 has a bearing section formed in the center thereof, consisting of a main bearing 40 and a lower bearing 9, and the main shaft 14 is supported by this bearing section. It has been inserted. Further, a fixed scroll member 5 is fixed to the frame 11 with a plurality of bolts, an orbiting scroll member 6 is engaged with the frame 11 by an Oldham mechanism 12 consisting of an Oldham ring and an Oldham key, and the orbiting scroll member 6 is connected to the fixed scroll member 5. On the other hand, it is formed so that it can rotate without rotating. A motor shaft 14b fixed to a motor rotor 3b is integrally connected to the main shaft 14 at its lower part, and the motor section 3 is directly connected thereto. A vertical suction pipe 17 is connected to the suction port 16 of the fixed scroll member 5 through the closed container 1, and the upper chamber 1a where the discharge port 10 is open is connected to the upper motor chamber 1b via passages 18a and 18b. It communicates with This upper motor room 1
b communicates with the lower motor chamber 1c via a passage 19 between the motor stator 3a and the side wall of the sealed container 1. Further, the upper motor chamber 1b communicates with a discharge pipe 20 passing through the closed container 1.

A back pressure chamber 41 is formed between the end plate 6a of the orbiting scroll member 6 and the frame 11.
1, the orbiting scroll member 6 is replaced with the fixed scroll member 5.
The intermediate pressure Pm is introduced from the compression chamber 7 through the pore 6e (see FIG. 4) of the end plate 6a of the orbiting scroll member. The lubricating oil is stored as an oil reservoir 22 in the lower part of the closed container 1. The upper end of the main shaft 14 is provided with an eccentric shaft portion (crank pin) 14a, and the eccentric shaft portion 14a is fitted into an orbiting bearing 39 (see FIG. 4) in a boss portion 6c of an end plate 6a of the orbiting scroll member 6. The main shaft 14 has a central vertical hole 13 for supplying oil to each bearing part.
It is formed from the bottom end to the top end surface. 13a is an oil lifting pipe that connects the lower end of the main shaft 14 and the bottom oil reservoir 22. A boss portion 6c of the orbiting scroll member 6 is provided at the lower part of the eccentric shaft portion 14a.
A balance weight 8, which will be described in detail later with reference to FIGS. 1 and 2, is formed integrally with the main shaft 14 on the upper part of the main bearing 40, which faces the front end surface of the main bearing 40. This balance weight 8 and
A balance weight 21 provided at the lower part of the electric motor rotor constitutes a first balance weight and a second balance weight, respectively, for canceling the centrifugal force accompanying the orbiting movement of the orbiting scroll member 6. The balance weight 8 rotates within the back pressure chamber 41.

Next, the flow of lubricating oil will be explained using FIGS. 3 and 4. In the figure, solid line arrows indicate the flow direction of refrigerant gas, and dashed line arrows indicate the flow direction of oil. The lower end of the oil lift pipe 13a immersed in the oil reservoir 22 receives a high discharge pressure Pd, while the area around the orbiting bearing 39 (see FIG. 4) and the main bearing 40 is Since the hole 6e receives an intermediate pressure Pm, which is the pressure during compression, the lubricating oil in the oil reservoir 22 at the bottom of the container rises in the center vertical hole 13 due to the pressure difference (Pd - Pm), and as such, The bearing section is lubricated by a differential pressure lubricating method using a central vertical hole. The lubricating oil rising inside the central vertical hole 13 is supplied to the main bearing 40 and the swing bearing 39. Note that the lower bearing 9 is lubricated with oil flowing up through the center hole 13 by the action of a centrifugal pump. The oil supplied to the bearings 39 and 40 is transferred to the back pressure chamber 4.
1 and the back pressure chamber 41 mixes with the refrigerant gas. As shown in FIG. 4, the oil supplied to the bearing 39 passes through the inner periphery of the recess 8b of the cylindrical balance weight 8, reaches the outer periphery of the boss portion 6c of the orbiting scroll, and reaches the outer periphery of the boss portion 6c of the orbiting scroll. Flows toward the sliding part. Therefore, by adopting this configuration, the Oldham ring portion 1
The lubricity of the second sliding part is improved. The mixture of oil and refrigerant gas then flows out into the compression chamber 7 via the back pressure hole 6e. The oil that has reached the compression chamber 7 is pressurized together with the refrigerant gas and moves to the discharge chamber 1a above the fixed scroll 5 and further to the motor chamber 1b. The refrigerant gas and oil are separated in the motor room 1b and the lower space 1c, and the oil is stored in an oil reservoir 22 at the bottom of the sealed container 1.
and is again supplied to each sliding part.

Now, FIGS. 1 and 2 are a plan view and a longitudinal cross-sectional view showing the shape of the balance weight 8 disposed in the back pressure chamber 41. As shown in FIG. The balance weight 8 has a cylindrical shape,
A circular recess 8b into which the boss portion 6c of the orbiting scroll member 6 can be inserted, and a circular attachment hole 8c into which the main shaft 14 is press-fitted are formed in a part thereof. The mounting hole 8c is a recess 8
It is continuous with b. A weight portion is formed by the remaining portion 8a excluding the recessed portion 8b and the attachment hole 8c. The center O2 of the recess 8b into which the boss 6c of the orbiting scroll member 6 can be inserted is the radius of revolution (the center of the eccentric shaft 14a relative to the center Of of the main shaft 14) with respect to the center Of of the main shaft 14 (that is, the center of the mounting hole 8c). On the other hand, the center O1 of the cylindrical outer circumference of the balance weight 8 is located in the opposite direction to the center O2 of the recess 8b with respect to the center Of of the main shaft 14, for example, with a turning radius. It is eccentric in the front and back dimension L. The above configuration forms the eccentric mass of the entire balance weight. The inner circumferential dimension R2 of the recessed portion 8b is determined to be slightly larger than the outer dimension of the boss portion 6c of the orbiting scroll. As the above dimension L increases, the distance between the center of gravity of the balance weight system increases and the external dimension R1 can be made relatively smaller.
(see FIG. 5), the above-mentioned dimension L cannot be increased carelessly. Here, from the viewpoint of the size restriction of the recessed portion 8b and practical dimensions (appropriate dimensions), the dimension L is set to be a dimension around the orbiting radius of the orbiting scroll.

FIG. 5 is an explanatory diagram showing the oil agitation pattern in which the balance weight 8 described above acts, and FIG. 6 is an explanatory diagram showing the oil agitation pattern in which the balance weight of the prior art acts. In the figure, the shaded area is the area (oil stirring area) where oil moves due to the rotation of the balance weight. In the embodiment of the present invention, the oil agitation area by the balance weight is much smaller than in the prior art, and therefore the power loss is small.

FIG. 7 is a plan view of another embodiment of the balance weight. In this embodiment, notches 8e are provided on both end surfaces of the balance weight 8 shown in FIGS. 1 and 2. This allows the balance weight 8 to be placed in the center of the frame on the main shaft 14 to avoid interference with the Oldham key groove catch of the frame 11.
The width dimension L5 is adjusted so that it can be easily assembled at an appropriate position.

FIGS. 9 and 10 are a plan view and a vertical sectional view of a balance weight according to still another embodiment. In this embodiment, a dissimilar metal 8f having a specific gravity greater than that of the material of the cylindrical balance weight body 8a is formed into an annular shape, and is integrally fitted to the outer circumference of the balance weight body 8a to balance the balance weight. It is characterized by comprising weights. The other configurations are the same as those in FIGS. 1 and 2.

FIGS. 11 and 12 are a plan view and a sectional view showing a balance weight according to still another embodiment. A fastening means 8g is formed on the upper surface of the notched outer peripheral part of the balance weight main body 8a.
It is integrally fixed to form a balance weight. The upper surface and circumferential surface of the dissimilar metal 8f are substantially aligned with the upper surface and circumferential surface of the balance weight main body 8a, respectively. Further, the center O1 of the balance weight main body 8a and the rotation center Of of the main shaft 14 are made to coincide. As a result, the area where oil moves as shown in Figure 5, that is, the oil agitation area, can be reduced to zero, and the balance weight can also be made smaller (thinner), thereby reducing oil agitation loss. It can be greatly reduced. Note that the dissimilar metal 8
Needless to say, f is provided on the opposite side of the eccentric direction of the recess 8b into which the boss 6c of the orbiting scroll member 6 is inserted.

FIGS. 13 and 14 show other embodiments and the shapes of their balance weights. FIG. 13 is a partial sectional view showing the structure of the balance weight 8 and its surroundings inside the back pressure chamber. FIG. 14 is a longitudinal sectional view of the balance weight. As shown in both figures, the cylindrical balance weight 8 has its upper end surface 8h aligned with the boss portion 6c of the orbiting scroll member 6.
The depth of the recess 8b into which the boss 6c is inserted is set to be long enough to reach the vicinity of the root of the vertically long (Z dimension shown in Fig.
The balance weight is set longer than in the case of 2) and has a slender shape (the dimension R1 can be made smaller). With this configuration, the distance Lc between the centrifugal force Fc acting on the orbiting scroll 6 and the centrifugal force Fb acting on the balance weight 8 becomes smaller than in other embodiments, and the joint moment thereof also becomes smaller. Therefore, it becomes easier to maintain balance around the main shaft, thereby further reducing shaft vibration and noise. The balance weight 8 used in this embodiment may be one in which the center O1 of its cylindrical outer periphery coincides with the center Of of the main shaft, or may be eccentric, or a Similar to the above-described embodiments, it may be made of metal.

FIG. 8 is an explanatory diagram showing the effect obtained by using the balance weight according to the present invention. As shown in this figure, according to the configuration of the present invention, the oil agitation loss due to the balance weight in the back pressure chamber can be significantly reduced compared to the conventional machine. This also has the effect of suppressing the rise in oil temperature in the slewing bearing and main bearing, combined with the reduction in bearing load due to the reduction in mechanical loss. The horizontal axis in FIG. 8 represents the drive frequency when the compressor motor is driven by an inverter, that is, the rotational speed of the main shaft 14, and it can be seen that the above-mentioned actions and effects become more pronounced as the speed increases.

Note that it is advantageous to use aluminum alloy, which is a lightweight material, for the orbiting scroll member 6 in order to increase the speed of the compressor. That is, the orbiting scroll member 6
As the weight is reduced, the balance weight can be made smaller (thinner), which greatly reduces oil agitation loss.Also, by reducing the centrifugal force acting on the slewing bearing, bearing loss is reduced. This is because it becomes even more effective in improving performance and reliability.

[0019]

[Effects of the Invention] The present invention has the following effects. (1) The performance of the compressor during high-speed operation can be significantly improved, and the operating range in the high-speed range can be widened. (2) In relation to item (1) above, the bearing load is significantly reduced and the lubricity of the sliding parts around the Oldham ring is improved, making the compressor reliable at high speeds. performance will greatly improve. (3) During high-speed operation, the balance weight does not receive extra fluid force when swinging around, so it is possible to reduce wasteful power consumption, reduce shaft vibration, and ultimately reduce noise.

[Brief explanation of the drawing]

FIG. 1 is a plan view of a balance weight according to an embodiment of the present invention;

[Figure 2] Longitudinal cross-sectional view of the same balance weight,

FIG. 3 is a longitudinal sectional view showing the overall configuration of a hermetic scroll compressor according to an embodiment of the present invention;

FIG. 4 is a partial cross-sectional view showing the structure around the balance weight in the back pressure chamber of the compressor;

FIG. 5 is an explanatory diagram showing the pattern of oil stirring caused by the balance weight,

FIG. 6 is an explanatory diagram showing the pattern of oil agitation caused by the balance weight of the prior art;

FIG. 7 is a plan view of a balance weight of another embodiment,

FIG. 8 is an explanatory diagram showing the effects of the present invention,

FIG. 9 is a plan view of a balance weight of still another embodiment,

[Fig. 10] A vertical cross-sectional view of the balance weight same as above,

[Figure 1
1] Plan view of balance weight of still another embodiment,

[Fig. 12] A vertical cross-sectional view of the balance weight same as above,

[Figure 1
3] Partial sectional view showing the structure around the balance weight of yet another embodiment,

FIG. 14 is a longitudinal sectional view of the balance weight in FIG. 13 above.

[Explanation of symbols]

3...Electric motor
5...Fixed scroll member 6...Orbiting scroll member 6c...Boss portion 8...Balance weight 8
a... Weight part 8b... Recessed part
8c...Mounting hole 11...Frame
12...Oldham mechanism 1
4...Main shaft
14a...Eccentric shaft portion 40...Main bearing

Claims (6)

[Claims] [Claim 1] A fixed scroll and an orbiting scroll each consisting of an end plate and a spiral wrap standing upright thereon are engaged with each other with the spiral wrap inside to form a compressor section, and a compressor section is constructed by protruding from the back surface of the end plate of the orbiting scroll. A main shaft having an eccentric shaft portion at an end that fits into a swing bearing in a boss is supported by a main bearing, a balance weight is fixed to the main shaft at a position between the main bearing and the boss, and a swing scroll is constructed. In a scroll compressor configured such that the member is rotated relative to a fixed scroll member by rotation of the main shaft without rotation thereof, the balance weight has a cylindrical shape partially having a recess into which the boss of the orbiting scroll member is inserted. The center of gravity of the cylindrical balance weight is eccentric with respect to the central axis of the main shaft in a direction opposite to the eccentric direction of the eccentric shaft portion, and the central axis of the recess is eccentric with respect to the central axis of the main shaft. In contrast, the scroll compressor is eccentric in the same direction as the eccentric direction of the eccentric shaft by a distance that is approximately the same as a turning radius (the eccentric distance of the central axis of the eccentric shaft from the central axis of the main shaft). . 2. The scroll compressor according to claim 1, wherein the center axis of the cylindrical balance weight is eccentric with respect to the center axis of the main shaft in a direction opposite to the center axis of the recess. . 3. The scroll compressor according to claim 1, wherein the central axis of the cylindrical balance weight coincides with the central axis of the main shaft. 4. The cylindrical balance weight includes:
Claims 1 and 2 characterized in that the peripheral portion is formed of a ring-shaped member made of a material having a higher specific gravity than other portions.
Or the scroll compressor according to 3. 5. The cylindrical balance weight includes:
Scroll compression according to claim 1, 2 or 3, characterized in that the substantially fan-shaped portion eccentric in a direction opposite to the eccentric direction of the recess is formed of a member made of a material having a higher specific gravity than other portions. Machine. 6. The concave portion is formed deeply so that the end surface of the cylindrical balance weight near the orbiting scroll member reaches near the root of the boss of the orbiting scroll member, thereby making the balance weight vertically long and thin. The scroll compressor according to any one of claims 1 to 5, characterized in that the scroll compressor has a shape.